Electrochemical sensor for amino acids based on gold nanoparticles/macroporous carbon composites modified glassy carbon electrode

Gold nanoparticles/macroporous carbon (GNPs-MPC) composites were simply fabricated by electrodepositing GNPs film on MPC using cyclic voltammetry (CV). The prepared composites were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectra (XPS) and X-ray diffraction (XRD). Glassy carbon electrode (GCE) modified with GNPs-MPC was used as electrochemical sensor of 1-tryptophane (L-Trp) and L-tyrosine (L-Tyr) for the first time. In 0.1 M PBS (pH = 7.4), the GNPs-MPC/GCE exhibited satisfactory electrocatalytic activity by significantly decreasing the oxidation potentials and increasing the peak currents of the oxidation of L-Trp and L-Tyr when compared with those modified electrodes. More importantly, the present electrode gave a wide linear range from 1.0 x 10(-5) M to 1.0 x 10(-3) M, 5.0 x 10(-6) M to 1.0 x 10(-3) M, a very low detection limit of 2.4 x 10(-8) M, 7.4 x 10(-8) M and a high sensitivity of 41 mu A mM(-1), 13 mu A mM(-1) for L-Trp and L-Tyr, respectively. Moreover, the electrode displayed a good reproducibility, a long-term stability and a favorable ability of anti-interference to electroactive-molecules. (C) 2012 Elsevier B.V. All rights reserved.